This invention relates to a novel method and means for decoding indicia from record media, and more particularly relates to a method means for identifying a unique symbol encoded by means of the use of bars of different widths and/or intervals on record media.
For purposes of increasing economy and efficiency of operation, a number of systems have been proposed involving the use of machine readable indicia in connection with various types of automated businesses such as supermarkets and other types of retail establishments, as well as banks, etc. Such machine-readable indicia may be employed on customer identification or credit cards, on articles sold in supermarkets, etc. Examples of such machine readable codes and associated apparatus for encoding and decoding may be found, for example, in U.S. Pat. Nos. 3,731,710; 3,731,064; 3,792,236; and Re. 28,198.
Particularly in the case of articles on which the wrapping or container includes thereon a large amount of other information, such as a picture and description of the goods, a trademark, etc., it is important that the machine-readable coded information also appearing thereon be distinguishable from the other information on the wrapping or container. This has been done in the past by using a special symbol or symbols to designate the beginning and end of the machine readable information. The importance of having such symbol or symbols, and assuring that they are readable without error by the decoding means, may readily be seen.
Certain factors may contribute to the difficulty of correctly identifying such symbols, such as the tendency of ink to spread slightly in the case of printed bar code information. A problem is also presented, in certain instances, when the background on which the information is to be encoded has certain characteristics which will appear to the decoding device to be similar to the encoded information. A successful decoding device must therefore be capable of correct decoding even in the event of some imprecision in the printing or other means employed for placement of the encoded information on the record media or article.